Centrifugal counter-current contacting apparatus



June 24, 1958 .J. PODBIELNIAK CENTRIFUGAL COUNTER-CURRENT CONTACTING APPARATUS IN1/nvm.- MJQJ sy A/ f ATTURNEY.

Filed July 6 2,840,301 Jiaueniealv June 24, 195s CENTRIFUGAL CUNTER-CURRENT CONTACTING APPARATUS Walter J. Podbielniak, Chicago, Ill., assignor of one-half to Wladzia G. Podbielniak Application July 6, 1955, Serial No. 520,203

4 Claims. (Cl. 233-15) Thisinvention relates to a. centrifugal countercurrent contacting method and apparatus wherein different phases, including` at least one liquid phase, are brought into contact for various purposes. The invention is particularly concerned with the contacting of immiscible liquidsof different densities.

The centrifugal counter-current contacting of immiscible liquids and other multi-phase systems has been practiced commercially for a number of years. AOne apparatus Vemployed for this purpose consists of a hollow casing mounted for rotation on a shaft, the casing containing a plurality of axially-concentric rings or drums which are each perforated around the entire circumference thereof. Therheavy phase, usually a liquid which may or may not contain solid material, is introduced at the central portion of the contacter while the con-p tactor is being rotated at high speed.y By the centrifugal force thus generated, the heavy liquid is impelled out-V wardly, flowing from ring to ring through the perforations therein.

tion of the contactor under sufficient pressure to cause it to ow countercurrently to the heavy phase through the ring perforations, both phasesy being likely to pass through the same perforations. While this counter-current radial flow of the two phases predominates, there is also some circumferential flow in the spaces between the rings, although this circumferential flow is necessarily' The light phase, either liquid, gaseous,' or both, issimultaneously introduced into thexouter'por- This invention is shown in illustrative embodiments in the accompanying drawing, in which- Fig. l is a somewhat schematic cross-sectional view o 'a'rotor embodying the present invention and adapted for use in a centrifugal contacting apparatus; Fig. 2, a view similar to that of Fig. 1,. showing a modified construction; and Fig. 3, another similar view showing a further modification.

Looking first at Fig. 1, there is schematically illus-` trated a cross-sectional viewl of a centrifugal contacter rotorrembodyin-g some of the features ofthe presentin-V vention. The hollow outer casing 10 is supportedA for rotation on a central shaft 11, and inside the casing 10 there is provided a plurality of spaced concentric cylindrical rings or drums 12a-12e. A These rings extend between the end walls of the rotor andare attached to theV end walls, as shown in my prior `Patent No.'2,670,132, thereby providing a plurality of laterally closed passageways. Each of the rings has a plurality of perforations 13 distributed around the entire circumferencethereof.

Also, near the outer periphery of v the contactor, vas-indii cated somewhat schematically atw14, there `isprovided an inlet for the light fluid, and outwardly yof inlet 14, an outlet 15 Vfor the heavy fluid, theA light fluid inlet being spaced inwardly of the heavy fluid outlet toprovide for final settling and clarification of the heavy fluid.

pacity and emulsion handling performance with a moderate number of stages is required. By emulsionhandling performance is' meant the ability of a contactor to overcome operational difficulties due to the tendency of the phases being contacted to'form emulsions. This might be accomplished either by controlling the contacting in such a way as to minimize emulsion formation or by providing for the breaking of emulsions after they are formed, or both.

vI t is' therefore a general object of this invention to handling and easily flushed. .Further objects and lad- A vantages will appear as the specification proceeds.

The heavy fluid is shown being supplied through a conduit 16 within shaft 11. The heavy fluid is passed from conduit 16 through `an inletgpipeA 17, which extends into ,theI passageway between the outer wall of shaft 11 and the innermost concentric ring 12u.V Inuthe illustration givenV an outlet 18 is shown consisting ofaport extending through the outer wall of shaft 11, thereby provid- Y mg communication between the annular space Within shaftll around conduit 16 and the` annular passageway between ring 12aand shaft 11. fA t The Ycontacter elements' just described, are similar tof those found in` present commercial centrifugal .contac.-V 1 tors, and theirdetailsof construction arewell known..` Therefore, itis not believedl that it will `be necessarydo' describe these elements. with greaterparticu1arity, or` other elements which are commonly associated there-gV with, such as the means for supplying and removing 4.the i' light and heavy fluids through the shaft ,11, the liquid seals associated with the shaft, the driving means for- In this connection, speciiicreference is C the shaft, etc. again made to my prior Patent No. 2,670,132 as disclosing further constructional details. y

Still looking at Fig. vl, I wish, however, -to call atten--l tion to the relatively large ports or orifices 19 which are found in each of the perforated rings 12o-12e. It will Y be` noted that the orifices 19 have a large crosssectional area as compared to that of the perforationsrl -Inthe illustration given, each of the rings is provided with onl asiugle orifice 19. i f

Preferably, as illustrated, the orifices 19 are respect to each other in adjacent rings. Where theannular passages between the rings are open andunobstructed, as illustrated in Fig. l, an approximate .offset in the orifices is desirable to provide for a maximum length;v

flow passage betweenA the orices, irrespective of the direction in which the fluid moves from orifice to iorific'e.. n

However, additional. orifices can be provided where shorter flow passages are desired, as`may be thecase.

with the outermost rings of a contactorrotor. 1"

Another important feature of this vinvention is illus-ir trated in one embodiment in Fig. 1.VV Specifically, inV accordance with .this invention, a nozzle 20' is mounted on each of the rings 12a- 12e over all of the orifices 19 and arranged to project in the same radial direction fromeach of the rings into the passageways';therebe` tween. For example, as shown n Fig. 1, the nozzles 20 offset with f all extendin a radially'outward direction from the rings on which'they are mounted. It will alsobe'noted that the nozzles 20 each terminate short of the next adjacent ring in the direction in whih they are extending, al-

though extending for wellover half the width ofthe annular passageways. A r With the embodiment ofFigf.` l, the heavyliquid, mayorrnayrnot` contain solid material, would-be introduced through. inlet nozzle 17 intotlie innermost annular passageway while the contacto` wasbeing rapidlyrotate'd". At the same time `the light uid, either liquid' or gaseous, would be'introducedunder pressure at 14 intothe outer portion of the contacter. After the contactor passageways have become filled with these fluidsl and a ow patteriiestablished, itwould be found that the ow ofthe hevy-liquidfv`vould Vbe primarily circumferential, while the ,flow f the l'glijtliqui'd would be substantially radial. lt/Iore'-4 speeically', the light liquidv would be owing inw'ardly fromrng to ring through perforations 13, while t the heavyliquidwouldtend to flow around the inner walls of ririgsf12a-@12e` and flowing therebetween primarily through orifices 19,` and nozzles 20. The heavy liquid ,being impelled outwardly by centrifugall force will tend totake the path'of least resistance, flowing around the `inrierfvlls*of the rings yarldtheri to the relatively large oritcesf19 andinozzleszoinstead'of through the perforations 13, `Thefpols-of light liquid which will be maintained dnvthe outer walls o f the rings will yalso act to retardflow of the heavy liquidl through the prerforations.A Thelight'iluid can not flow through the nozzles 20 or the orifices 191 until the bands of light -liqui'd on the outer walls.` 4of' the rings reachedra depth corresponding to that of the lengthfofjthenozzles 20. Thus, over a wide range of` flow` ratios, Vthe-,indicated ow patterns can be established and maintained. i v

Since" the` heavy liquid the embodiment of Fig- 1 tendsto How throught orifices 1,9` and nozzles 20 rather A than through perfor-'ations 13, there will be a reduced tendency vfurthe p'erfo'ratious- 13 to become plugged with p solid material which is carried inthe heavy liquid. This advantage willvb'e particularly marked when the solids are ligl'ttei'l thanthe heavy liquid and tend to Yaccumulate'at theinterfacebetween the two liquids. The .pre-

W dominate'dow of the light liquid through 4the perfora tions to substantial'exclusion of the `heavy liquid will tendf to wash the solids'aWay from the pcrforations even if the solids are heavier'than-fthe heavy phase.

Aufr'slate'd advantg'swxislts with Aall two-phase systems whichtend to formstableemulsions when the phases are simultaneously passed through'` small perforations, such as perforations 13. The attritional interaction of the',

uid phases as they are simultaneously forced through small perforations is largely 'avoided with the embodiment ofFigLjl. The lightphase isy passed through the.

perforations in the concentric rings while the reverse flow of the heavy phase is mini'rniied.` At the same time, etectiv'e contactis'obtainedA because the light phase as it passes through each :ring is `dispersed in' theV circumferentially flowing stream of heavy liquid along the inner walls of the ring. 'Then' the light liquid isV allowed to collect and settle alon'gfthe'inn'e'r walls of the next ring,

thereby providingalternate mixing vand clarifcation'with'- t out the necessity for passing both 'liquids through fthe ring, perforations.`

When Vthe uids are present inthe. contactor `in disproportionate'volumes, as` would 4result from' widely different tlowrates of the two uids, the continuous circumferential. versus radial flow pattern of this inventionxcan be advantageous in preventing" channelling; For 'example, in the'embodirnentofFig; 1,:theheavy `iuidlcould be'presentin a much largervolumet than 'the'light' uid,

while `still being directed in'a, continuous generally circumferential owfpathffroxni ringh to' ring. The? smaller volume oflight liquidcoulil alsostilll have fap'redominantly radial flowypassing throulghftleiperforations 13, and

' tactor.

ferential paths along the inner walls of the rings it is preferred, as illustrated in Fig. 1, to have the angular ring portions directly opposite the nozzles made im- .Y porate.

soV

The embodiment shown in Fig. 2 is substantially the same as that of Fig. 1', exceptthat the nozzles 20' extend radially inward from the concentric rings, insteadof radially outward. However, to indicate that Fig. 2 is a modification, as already suggested, the corresponding parts have' been given the same numbers with a prime affixed thereto. It will also be understood that with the embodiment of Fig. 2, the heavy liquid will have a predominantly radial ow while the light liquid will have a predominantly circumferential flow. More specifically, thelight liquid, after owing around theA outerwalls of the perforated rings 12a`12e' will flow inwardly to the next concentric ring through orifices 1'9 and nozzles 20',

vwhile the heavy'liquid will ow outwardly through perforations- 13', collecting in bands or pools along the inner walls of the rings to the height of nozzles 20. construction might be more advantageous than that' of Fig. 1 where the light liquid is present'in a much greater volume than Vthe heavy liquid, or where the light liquid has a greater tendency to emulsify in the heavy liquid, when dispersed therein, than does the heavy liquid upon dispersal in the light liquid.

The embodiment of Fig. 3 is also similar to that of Fig. l, the corresponding parts being the same numbers, the numbers being double primed, to indicate the modiiication. The principal difference between the constructions rof Fig. l and Fig. 3 is that in Fig. 3 -there are provided obstructions 21 extending across the annular passageways between the rings and-'arranged toV substantially block Vcircumferential llow beyond the nozzles 20" in one circumferential direction. In 'the illustration given,

obstructions 21 are in the form of radially extendingV plates having laterally turned feet which rest on the adjacent'walls of the perforated rings.` Preferably, plates 21' extend' for the full width and length of the Vannular passageways, thereby completely preventing circumferentialow in one direction from the nozzles 20 around the annular passageways.

`As shown in Fig. 3, the obstructions 21 in radially adjacent passageways are vin opposite circumferential reof the perforated lrings will .then be alternately clockwise andA counter-clockwise, irrespective'of the direction of rotation of the contactor. If desired, additional nozzles and adjacent `obstructions can be provided.

With all three embodiments shown in the drawing, it is assumed that the direction of'rotation is counter-clock-A wise, as illustrated by the rotational arrows on the various figures of the drawing. Assuming a counter-clockwise direction of rotation then, the circumferential flow of the heavy liquid in the embodiment of Fig l and the light liquid in the embodiment of Fig. 2, will be predominantly Iin the` direction of rotation ofthe -contactors due to the socalled swirl effect. This will tend to minimize remixing of the collected light phase on the outer walls 'in the arrangement of Fig. 1, or the collected heavy phase on the inner walls with the arrangementof Fig. 2. On the other hand, with the arrangement of Fig. 3, -in .alternate passageways where the ow of the heavy liquid is opposite to the ldirection of rotation of the contactor,

there will be a great deal of turbulence andy consequent This' remixing of the light and heavy phases. =For example, as shown in Fig. 3, the heavy uid will be owing circumferentially in the ldirection of rotation of the contactor in the innermost annular passageway, and therefore would have a lesser tendency to remix with the collected band of light fluid around the outer wall of shaft 11". In the next outwardly passageway, the opposite would be the case, and so on.

Generally, the apparatus and method described herein can be employed for counter-current contact vbetween liquid and gages or vapors. For example, the invention can be used in such chemical processing functions as solvent extraction, decolorizing, removing impurities from liquid compositions and chemically interacting two or more liquids. It may also `be employed in distillation, reliux extraction, gas absorption, dehumidification, and like processes. However7 the use of the invention in carrying out liquid-liquid extractions is particularly advantageous, especially where the particular liquid-liquid extraction has one of the liquid phases in relatively small volume and/ or where it is not desirable to disperse both of the liquid phases. For example, the embodiment of Fig. l would be particularly useful for extracting a petroleum naphtha solution of unrefined wood rosin with furfural. The naphtha solution of rosin, being the light phase, would be repeatedly dispersed in the `continuously owing stream of furfural, and the furfural would be used at a high volume ratio compared to the naphtha solution of rosin.

As a desirable specific application for the embodiment of Fig. 2 can be mentioned the furfural extraction of degumrned soybean oil. Here again, the furfural would be the heavy phase and would =be present in much greater volume than the lighter soybean oil. However, this time to promote efficient contact it is desirable to repeatedly disperse and collect the furfural. Therefore, the soybean oil is caused to flow inwardly along circumferential paths while the furfural flows outwardly along radial lines, being dispersed into the flowing stream of soybean oil as it passes through the ring perforations, and then collecting on the inside surface of the next outer ring before passing throughthe perforations therein.

The sulfuric acid refining of crude gasoline could also be advantageously carried out in the embodiment of Fig. 2. The heavier sulfuric acid `could be brought into intimate `contact with the -crude gasoline, while the gasoline could be present in a much larger volume than the sulfuric acid.

The construction of Fig. 3 provides long circumferential ow paths for `the heavy liquid, which arealternately turbulent and relatively smooth. This arrangement would lend itself well to the `de-asphalting of residual oil or reduced crudes with propane. The residual oil would move outwardly along the circumferential iiow paths, being the heavier phase, while the propane would liow inwardly through the perforations and thereby vbe dispersed in the residual Ioil streams adjacent the inside of each ring. Further, within the passageways where the residual oil is iiowing in a direction opposite to that in which the contactor is being rotated, both phases will be continually remixed, thereby increasing the effectiveness of the contacting without sacrificing ultimate clarification and separation of the phases. It will be noted that in the loutermost and innermost passageways the residual oil will be flowing in the direction of rotation, `as indicated in Fig. 3.

While in the foregoing specification this invention has been described in relation to specific embodiments thereof and many `details have been set forth for purpose of i1- lustration, it will be apparent to those skilled in the art that the invention is subject to other embodiments and that many of the details can be varied widely without departing from the basic principles of the invention.

I claim: v

1. In a centrifugal contact'apparatus, a rotor including a plurality of concentric perforated rings providing annular passageways therebetween, `said passageways being laterally closed, at least one orifice in each of said rings having a large cross-sectional area compared to that of the perfora'tions therein, and a nozzle mounted on each of said rings over said oriiices, said nozzle projecting in only one radial direction from said rings into said passageways but terminating short of the next adjacent ring.

2. The apparatus of claim l wherein there is provided obstructions across said passageways positioned adjacent said nozzles and arranged to substantially lblock circumferential flow beyond said nozzles in one circumferential direction from each of said nozzles. n

3. The apparatus of claim 2 which is characterized by the further fact that the obstructions in radially adjacent passageways are in opposite circumferential relation to said nozzles therein to block the ow beyond the noz-y References Cited in the file of this patent Y UNITED, STATES PATENTS 2,281,796 Podbielniak May s, i942 

